Supporting structure of pressure vessel

ABSTRACT

A supporting structure of a pressure vessel is disclosed in which a footing formed integral with the lower edge of the side wall of the pressure vessel is placed within an annular recess formed in the concrete foundation and securely held in position by anchor bolts and concerete blocks are disposed in the annular recess inside the pressure vessel thereby holding firmly the footing in position. Intermediate members are interposed between the concrete foundation and the concrete blocks. When the side wall and hence the footing of the pressure vessel is raised as the internal pressure is increased, only the concrete blocks are raised while the concrete foundation, that is the concrete floor remains in the same position. Therefore no excessive forces are exerted to the concrete foundation or floor so that cracking thereof may be prevented. A portion of a liner support, which is embedded in the concrete foundation within the pressure vessel for supporting thereupon a lining plate, adjacent to the inner wall of the pressure vessel is cut off and is not welded to the lining plate so that the deformation of the lining plate is permitted when the footing is raised. Thus the stress concentration at the joint between the pressure vessel and the lining plate can be prevented, whereby the lining plate may be prevented from being damaged.

United States Patent [1 1 Yoshinaga et al.

[ Dec. 23, 1975 1 SUPPORTING STRUCTURE OF PRESSURE VESSEL [75]Inventors: Toshiaki Yoshinaga; Takanao Wada; Kenji Matsuo, all ofHitachi, Japan [73] Assignee: Hitachi, Ltd., Japan [22] Filed: Nov. 12,1973 [21] Appl. No.: 414,747

[30] Foreign Application Priority Data Nov. 15, 1972 Japan 47-113898[52] US. Cl. 52/169; 52/247; 52/295; 52/573 [51] Int. Cl. E02d 27/00;EO4b l/92 [58] Field of Search 52/247, 249, 169, 224, 52/274, 295, 573;220/1 B, 18; 61/46 [56] References Cited I UNITED STATES PATENTS l,l38,394 5/1915 Mueser ..l 52/247 1,290,093 1/1919 Cole 220/1 B1,964,870 7/1934 Chappell..... 220/1 B 2,301,061 11/1942 Logeman....220/18 2,336,958 10/1945 Jackson 220/18 3,605,362 9/1971 Sweeney 52/2243,791,152 2/1974 Davis et al. 61/46 FOREIGN PATENTS OR APPLICATIONS718,606 11/1954 United Kingdom 220/1 B i [lull Primary Examiner-Ffank L.Abbott Assistant Examiner James L. Ridgill, Jr. Attorney, Agent, orFirmCraig & Antonelli [57] ABSTRACT A supporting structure of a pressurevessel is disclosed in which a footing formed integral with the loweredge of the side wall of the pressure vessel is placed within an annularrecess formed in the concrete foundation and securely held in positionby anchor bolts and concerete blocks are disposed in the annular recessinside the pressure vessel thereby holding firmly the footing inposition. Intermediate members are interposed between the concretefoundation and the concrete blocks. When the side wall and hence thefooting of the pressure vessel is raised as the internal pressure isincreased, only the concrete blocks are raised while the concretefoundation, that is the concrete floor remains in the same position.Therefore no excessive forces are exerted to the concrete foundation orfloor so that cracking thereof may be prevented. A portion of a linersupport, which is embedded in the concrete foundation within thepressure vessel for supporting thereupon a lining plate, adjacent to theinner wall of the pressure vessel is cut off and is not welded to thelining plate so that the deformation of the lining plate is permittedwhen the footing is raised. Thus the stress concentration at the jointbetween the pressure vessel and the lining plate can be prevented,whereby the lining plate may be prevented from being damaged.

15 Claims, 7 Drawing Figures US. Patent Dec. 23, 1975 Sheet 1 of33,927,497

FIG.

FIG. 3

US Patent Dec. 23, 1975 Sheet20f3 3,927, 37

FIG.2

US. Patent Dec. 23, 1975 Sheet 3 of3 3,927,497

SUPPORTING STRUCTURE or PRESSURE VESSEL BACKGROUND 01 THE INVENTION Thepresent invention relates to a supporting structure of a pressure vesseland especially of a nuclear reactor containment vessel.

In general .a nuclear reactor such as a boiling-water type reactor isplaced within a reactor containment vessel in order to prevent therelease of significant radioactivity to the environment due to thebreakdown of the coolant circulation system. Therefore carefulconsideration has been given in design of a nuclear reactor containmentvessel and its supporting structure in order to give the specialassurance to the safety of a reactor. However the conventionalsupporting structure of a reactor containment vessel is not satisfactoryto give the maximum assurance to thesafety of a nuclear reactor as willbe described hereinafter.

The footing of the conventional reactor containment vessel is embeddedinto a concrete foundation and is securely held in position by means ,ofanchor bolts. Thereafter concrete is placed to embed the anchor belts inthe concrete foundation. The edge of a lining plate which is placed uponthe concrete floor within the containment vessel is welded to the innerwall of the containment vessel to provide a bottom thereof. Thus, thelining plate provides the airand water-tightness to prevent the releaseof radioactivity to the'environment. In order to prevent the deformationof the lining plate due to its thermal expansion, it is welded to upperends of liner-supports embedded in the concrete floor within thecontainment vessel.

When the internal pressure is increased within the containment vesseldue to the breakdown of the coolant circulation system of a nuclearreactor contained or in case of an earthquake, the side of thecontainment vessel is subjected to the tensile forces which act upwardlyso that the anchor bolts are forced to elongate with the result of therise of the footing of the containment vessel. As a result many cracksare propagated in the concrete floor with the result of the dangerousdecrease in load bearing capability thereof. The concrete floor orfoundation cannot contain the internal pressure or cannot withstand theforces exerted thereto in case of an earthquake once cracks arepropagated in the concrete floor or foundation. If the initialtightening loads of the anchor bolts are increased, the elongation ofthe anchor bolts in case of the increase in internal pressure or in caseof an earthquake may be prevented to some extent. However this methodcannot overcome the fundamental defects of the conventional supportingstructure of a reactor containment vessel because of the creep in theconcrete foundation, relaxation of the anchor boltsand the retighteningof the anchor bolts which must be carried out periodically.

Furthermore when the footing is raised or floated, the lining platewelded to the inner wall of a containment vessel is subjected todeformation. As a result considerably great stress concentrations areinduced in the joint between the lining plate and the inner wall ofthecontairlment vessel, and in the worst case the lining will beseriously damaged. The lining plate which is generally thin and isprovided for the purpose of pre ventingthe release of radioactivity tothe environment must-be free from the stress concentration due to thedeformation thereof. The internal pressure acting upon 2 the liningplate is received by the concrete foundation below the lining plate.

SUMMARY OFTHE INVENTION capable of preventing the deformation of aliningplate,

which forms the bottom of the pressure vessel, and the resulting stressconcentration. Briefly stated, the most important feature of the presentinvention resides in the fact that the footing of a pressure vessel isplaced within a recess formed in a concrete foundation and is securelyheld in position by means of anchor bolts embedded in the concretefoundation and concrete blocks with intermediate members beinginterposedl between the concrete blocks and the concrete foundation.

Another important feature of the present invention is provision of thestress relieving means which are disposed adjacent to the joint betweenthe edge of the lining plate and the inner wall of the pressure vessel.

The above and other objects, features and advantages of the presentinvention will become more apparent from the following description ofpreferred embodiments thereof taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a vertical sectional view ofa first embodiment of the present invention applied to a nuclear reactorcontainment vessel;

FIG. 2 is a fragmentary sectional view, on enlarged scale, illustratinga portion indicated by II in FIG. 1;

FIG. 3 is a cross sectional view taken along the line III--III of FIG.1;

FIG. 4 is a cross sectional view taken along the line IVIV of FIG. 3;

FIG. 5 is a cross sectional view taken along the line V V of FIG. 4; and

FIGS. 6 and 7 are sectional views of second and thir embodiments,respectively, of the present invention.-

Same reference numerals are used to designate similar parts throughoutthe figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment, FIGS. 1 S

In the embodiments to be described hereinafter, the present inventionwill be explained as being applied to a boiling-water type nuclearreactor. FIG. 1 shows the supporting structure of a reactor containmentvessel generally indicated by numeral 1. The containment vessel 1 has afooting generally indicated by 2 and extended from the lower end of aside wall and anchored securely to a concrete floor or foundation 4 byanchor bolts 5. Between the containment vessel 1 and a concrete shield 7and close to the concrete floor or foundation 4 is formed a pit 9 intowhich is filled sand.

The pit 9 may be formed between the containment vessel 1 and theconcrete foundation 4. Within the containment vessel 1 and upon theconcrete floor or foundation 4 is laid a lining plate 11 whose edge iswelded to the inner wall of the containment vessel 1. The lining plate11 is also securely joined to liner supports 13 embedded into theconcrete foundation 4. The liner supports are securely fixed to theconcrete foundation by anchor bolts 14. The anchor bolts and 14 areanchored to a concrete foundation mat 15 below the concrete floor orfoundation 4.

FIG. 2 is a fragmentary sectional view, on enlarged scale, of thecontainment vessel 1 shown in FIG. 1. The footing 2 of the containmentvessel 1 comprises a flange 22 joined to the inner wall of thecontainment vessel 1, a base or foot plate 20, 'outer stays 24 joined bywelding to the outer wall of the containment vessel 1 and its base plateand inner stays 21 joined by welding to the inner wall of thecontainment vessel 1, its flange 22 and base plate 20. The flange 22 isconnected by a suitable weld joint as at 23 to the inner wall of thecontainment vessel 1. The base plate 20 is fixed to the lower edge ofthe side wall of the containment vessel 1 by welding. The footing 2 ofthe containment vessel 1 is placed in an annular groove 26 in theconcrete foundation or floor 4. Alternatively, the footing 2 may bedivided into a plurality of sections which may be placed in a pluralityof arcuate recesses formed in the concrete floor 4 along the samecircle. The base plate 20 is securely held in position by the anchorbolts 5 embedded in the foundation mat 15. After the nuts 6 of theanchor bolts 5 are securely tightened, they are welded to the base plate20 to prevent the loosening of the nuts 6. The upper surface of theflange 22 substantially flushes with the surface of the concrete floor 4within the containment vessel 1 when the containment vessel 1 isinstalled. The anchor bolts 5 are interconnected with each other by ananchor plate 28.

The liner suports 13 are embedded within the concrete floor 4 in theform of a grill as best shown in FIG. 3, and are securely held inposition by the anchor bolts 14. Upon the lining supports 13 is laid thelining plate 11 and welded thereto. The edge of the lining plate 11 iswelded to the flange 22 jointed to the inner wall of the containmentvessel 1. The welded portion between the lining plate 11 and the flange22 is designated by numeral 25. Because the diameter of the bottom ofthe containment vessel 1 and hence the diameter of the inner plate 11 isgenerally large, the lining plate 11 is divided into a plurality ofsections in order to facilitate the fabrication and transportation, andthe component parts of the lining plate 11 are assembled by welding onthe field.

The joint between the liner supports 13 and the lining plate 11 is bestshown in FIG. 4. The sections of the lining plate 11 are welded togetheralong the liner support 13 at 33 and also welded thereto. The upperportion of the web of the liner support 13 adjacent to the lining plateis cut off as indicated by 34 (See FIG. 2) a predetermined length at theend of the liner support 13 adjacent to the inner wall of thecontainment vessel 1. The section of the cut off portion 34 is shown inFIG. 5, in detail.

Referring back to FIG. 2, concrete blocks 36 are disposed between theinner wall of the containment vessel 1 and the inner wall of the annularrecess 26 in the concrete floor 4 and between the flange 22 and the baseplate 20. An intermediate member 38 made of paper, a thin wooden ormetal plate is interposed between the concrete block 36 and the innerwall of the annular recess 26.

The upper surface of the concrete block 36 is made into contact withunder surfaces of the flange 22 and the lining plate 11. Alternatively,the length of the flange 22 may be so determined as to cover the wholeupper surface of the concrete block 36.

The portion of the annular recess 26 outside of the footing 2 of thecontainment vessel 1 defines the bottom of the pit portion 9 into whichis filled sand. Sand is also filled in the space above the footing 2.Instead of sand, gravel may be used.

When the internal pressure inside the containment vessel 1 increases orin case of an earthquake, the supporting structure of the containmentvessel in accordance with the present invention can absorb the externalforces. The mode of absorbing the external shocks produced when theinternal pressure is increased due to the breakdown of the coolantcirculation system (not shown) will be described hereinafter. Thepressurized and high temperature steam fills the containment vessel 1 sothat the upward forces are exerted to the footing 2. The anchor bolts 5are exerted with the tension so that they are elongated. Then thefooting 2 is moved upwardly as indicated by the two-dot lines in FIG. 2.That is, the undersurface of the base plate 20 is raised to the levelindicated by the two-dot lines A so that the concrete blocks 36 are alsoraised. Since the concrete blocks 36 are separated from the concretefloor 4 by the intermediate members 38, no crack is produced orpropagated in the concrete floor 4 even when the concrete blocks 36 areraised. Furthermore sand is filled in the annular recess 26 outside ofthe containment vessel 1 so that even when the footing 2 is raised nocracking is produced in the concrete floor 4 outside of the containmentvessel 1. Sand in the pit portion 9 serves to prevent the stressconcentrations upon the wall of the containment vessel 1 close to thefooting 2 thereof.

When the footing 2 is raised or floated, the lining plate 11 issubjected to deformation. Since the cut off portions 34 are provided inthe liner supports 13, the stress produced in the lining plate 11 may besufficiently relieved. That is, at the cut off portions 34, the liningplate 11 is free to bend itself. Therefore the lining plate 11 may beprevented from being damaged, and the joint between the lining plate 11and the flange 22 may be also prevented from being damaged. Thus theairand water-tightness of the containment vessel 1 may be maintained.

As described hereinbefore, according to the present invention, crackingof the concrete foundation as well as breaking of the lining plate maybe prevented so that the safety of the containment vessel may be muchimproved. Furthermore the step of tightening the anchor bolts may beeliminated.

Second Embodiment, FIG. 6

The second embodiment shown in FIG. 6 is substantially similar inconstruction to the first embodiment described hereinbefore exceptadditional concrete blocks 40 are placed upon the base plate 20 in theannular recess 26 outside of the containment vessel 1 to prevent thenuts of the anchor bolts 5 from loosening. The concrete blocks 40 arespaced apart from the outer side wall of the annular recess 26 so thatsand in the pit portion 9 may fill the space therebetween. The

Third Embodiment, FIG. 7

The third embodiment shown in FIG. 7 is substantially similar to thesecond embodiment shown in FIG. except that the concrete blocks 40 fillthe annular recess 26 outside of the containment vessel 1 upon the baseplate 20 thereof, thereby forming the bottom of the pit portion 9.Between the outer side wall of the annular recess 26 and the concreteblocks 40 are interposed intermediate members 42 similar to theintermediate members 38 between the inner wall of the annular recess 26and the inner concrete block 36 inside the containment vessel 1.

So far the present invention has been described as being applied to thenuclear reactor containment vessel, but it is understood that thepresent invention may be also applied to pressure vessels for storingtherein semi-finished products or the like which may produce heat and/orgas, whereby the internal pressure may be increased. It is alsounderstood that various modifications can be effected without departingfrom the true spirit of the present invention.

What is claimed is:

1. A supporting structure of a pressure vessel comprising:

footing means secured to a lower edge of a side wall of said pressurevessel for installing the vessel on a concrete foundation,

said footing means including a base plate fixed on the lower edge of theside wall of said pressure vessel and a lining plate support memberjoined to the inner surface of said side wall so as to projecttherefrom,

liner support means installed in the concrete foundation inside the sidewall of said pressure vessel,

a lining plate mounted on the liner support means and fixed to thelining plate support member at the edge thereof to form the bottomsurface of the pressure vessel,

said lining plate and said lining plate support member having thereunderconcrete for reinforcing them, and

a first means disposed adjacent to an inner edge of the base plate at anend thereof and to an under surface of the lining plate at the otheropposite end thereof for permitting the concrete on the base plateinside the side wall of the vessel to be moved with the base plate, whenan unusual pressure increase occurs in the pressure vessel,

said liner support means having means for relieving the stress producedin the lining plate when an unusual pressure increase occurs in thepressure vessel said relieving means being disposed at ends thereoffacing said first means.

2. A supporting structure of a pressure vessel as set forth in claim 1,further comprising an annular recess provided on the concrete foundationwhich reinforces the lining plate for disposing therein said footingmeans, said first means being disposed on the inner side wall of saidannular recess for separating the concrete on the base plate inside theside wall of said pressure vessel from the inner side wall of saidannular recess, thereby permitting said concrete to be moved when anunusual pressure increase occurs in the pressure vessel.

6 ,3 3. A supporting structure of -a pressurevessel as set forth inclaim- 2, wherein said-liner support means are provided with cut offportions at ends thereof facing said first means. j

4. A supporting structure of a pressure vessel as set forth in claim 2further comprising a pit portion formed between the outer surface of theside wall of said pressure vessel and a concrete structure provided onthe concrete foundation outside of the side wall of the pressure vesselin communication with the annular recess outside of the pressure vessel,said pit portion containing filler.

5. A supporting structure of a pressure vessel as set forth in claim 4,wherein said liner support means are provided with cut off portions atends thereof facing said first means.

6. A supporting structure of a pressure vessel as set forth in claim 4further comprising concrete blocks fixed on the base plate outside ofthe pressure vessel and a space formed between said concrete blocks andthe outer side wall of the annular recess, said space containing thefiller in the pit portion.

7. A supporting structure of a pressure vessel as set forth in claim 6,wherein said liner support means are provided with cut off portions atends thereof facing said first means.

8. A supporting structure of a pressure vessel as set forth in claim 1further comprising a pit portion formed between the outer surface of theside wall of said pressure vessel and a concrete structure provided onthe concrete foundation outside of the side wall of the pressure vessel,said pit portion containing filler.

9. A supporting structure of a pressure vessel as set forth in claim 8further comprising concrete blocks fixed on the base plate outside ofthe pressure vessel and a space formed between the concrete blocks andthe inner side wall of the pit portion, said space containing the fillerin the pit portion.

10. A supporting structure of a pressure vessel as set forth in claim 9,wherein said liner support means are provided with cut off portions atends thereof facing said first means.

11. A supporting structure of a pressure vessel as set forth in claim 8,wherein said liner support means are provided with cut off portions atends thereof facing said first means.

12. A supporting structure of a pressure vessel as set forth in claim 1further comprising a pit portion formed between the outer surface of theside wall of said pressure vessel and a concrete structure provided onthe concrete foundation outside of the side wall of the pressure vessel,and a second means disposed on an inner side surface of the pit portionand adjacent to an outer edge of the base plate at an end thereof, forseparating concrete placed on the base plate outside of the pressurevessel from the inner side surface of the pit portion, therebypermitting the concrete to be moved when an unusual pressure increaseoccurs in the pressure vessel.

13. A supporting structure of a pressure vessel as set forth in claim12, wherein said liner support means are provided with cut off portionsat ends thereof facing said first means.

14. A supporting structure of a pressure vessel as set forth in claim 2further comprising a second means disposed on an outer side surface ofthe annular recess and adjacent to an outer edge of the base plate at anend thereof for separating concrete placed on the base 7 8 plate outsideof the pressure vessel from the-outer side 15. A supporting structure ofa pressure vessel as set surface of the annular recess, therebypermitting the forth in claim 14, wherein said liner support means areconcrete to be moved when an unusual pressure inprovided with cut offportions at ends thereof facing crease occurs in the pressure vessel.said first means.

1. A supporting structure of a pressure vessel comprising: footing meanssecured to a lower edge of a side wall of said pressure vessel forinstalling the vessel on a concrete foundation, said footing meansincluding a base plate fixed on the lower edge of the side wall of saidpressure vessel and a lining plate support member joined to the innersurface of said side wall so as to project therefrom, liner supportmeans installed in the concrete foundation inside the side wall of saidpressure vessel, a lining plate mounted on the liner support means andfixed to the lining plate support member at the edge thereof to form thebottom surface of the pressure vessel, said lining plate and said liningplate support member having thereunder concrete for reinforcing them,and a first means disposed adjacent to an inner edge of the base plateat an end thereof and to an under surface of the lining plate at theother opposite end thereof for permitting the concrete on the base plateinside the side wall of the vessel to be moved with the base plate, whenan unusual pressure increase occurs in the pressure vessel, said linersupport means having means for relieving the stress produced in thelining plate when an unusual pressure increase occurs in the pressurevessel said relieving means being disposed at ends thereof facing saidfirst means.
 2. A supporting structure of a pressure vessel as set forthin claim 1, further comprising an annular recess provided on theconcrete foundation which reinforces the lining plate for disposingtherein said footing means, said first means being disposed on the innerside wall of said annular recess for separating the concrete on the baseplate inside the side wall of said pressure vessel from the inner sidewall of said annular recess, thereby permitting said concrete to bemoved when an unusual pressure increase occurs in the pressure vessel.3. A supporting structure of a pressure vessel as set forth in claim 2,wherein said liner support means are provided with cut off portions atends thereof facing said first means.
 4. A supporting structure of apressure vessel as set forth in claim 2 further comprising a pit portionformed between the outer surface of the side wall of said pressurevessel and a concrete structure provided on the concrete foundationoutside of the side wall of the pressure vessel in communication withthe annular recess outside of the pressure vessel, said pit portioncontaining filler.
 5. A supporting structure of a pressure vessel as setforth in claim 4, wherein said liner support means are provided with cutoff portions at ends thereof facing said first means.
 6. A supportingstructure of a pressure vessel as set forth in claim 4 furthercomprising concrete blocks fixed on the base plate outside of thepressure vessel and a space formed between said concrete blocks and theouter side wall of the annular recess, said space containing the fillerin the pit portion.
 7. A supporting structure of a pressure vessel asset forth in claim 6, wherein said liner support means are provided withcut off portions at ends thereof facing said first means.
 8. Asupporting structure of a pressure vessel as set forth in claim 1further comprising a pit portion formed between the outer surface of theside wall of said pressure vessel and a concrete structure provided onthe concrete foundation outside of the side wall of the pressure vessel,said pit portion containing filler.
 9. A supporting structure of apressure vessel as set forth in claim 8 further comprising concreteblocks fixed on the base plate outside of the pressure vessel and aspace formed between the concrete blocks and the inner side wall of thepit portion, said space containing the filler in the pit portion.
 10. Asupporting structure of a pressure vessel as set forth in claim 9,wherein said liner support means are provided with cut off portions atends thereof facing said first means.
 11. A supporting structure of apressure vessel as set forth in claim 8, wherein said liner supportmeans are provided with cut off portions at ends thereof facing saidfirst means.
 12. A supporting structure of a pressure vessel as setforth in claim 1 further comprising a pit portion formed between theouter surface of the side wall of said pressure vessel and a concretestructure provided on the concrete foundation outside of the side wallof the pressure vessel, and a second means disposed on an inner sidesurface of the pit portion and adjacent to an outer edge of the baseplate at an end thereof, for separating concrete placed on the baseplate outside of the pressure vessel from the inner side surface of thepit portion, thereby permitting the concrete to be moved when an unusualpressure increase occurs in the pressure vessel.
 13. A supportingstructure of a pressure vessel as set forth in claim 12, wherein saidliner support means are provided with cut off portions at ends thereoffacing said first means.
 14. A supporting structure of a pressure vesselas set forth in claim 2 further comprising a second means disposed on anouter side surface of the annular recess and adjacent to an outer edgeof the base plate at an end thereof for separating concrete placed onthe base plate outside of the pressure vessel from the outer sidesurface of the annular recess, thereby permitting the concrete to bemoved when an unusual presure increase occurs in the pressure vessel.15. A supporting structure of a pressure vessel as set forth in claim14, wherein said liner support means are provided with cut off portionsat ends thereof facing said first means.